Home >> Science & Nature >> Rocks & Minerals

Properties & Characteristics of Rubies

Ruby gemstones get their name from the Latin word ruber, meaning red. The value of rubies, like diamonds, is based on carats. The deeper the red and clearer the stone, the more valuable it will be. Rubies have been found across the world, but some areas are more known for them than others. Asian countries, including Myanmar, Thailand and Pakistan, are main exporters, although they have also been found in the U.S., Kenya and Greenland.

Chemical Properties
- The chemical makeup of rubies is very simple. They consist mainly of aluminum and oxygen. The presence of chromium is what turns the ruby red. The chromium only makes up wither 0.03 to 0.05 percent of the gem's weight.
Color
- The color of a ruby is the most important valuation tool. The deeper the red, the more valuable it is. To be classified as a ruby the gemstone must be red. Pink rubies are more commonly called pink sapphires. The most expensive rubies are called "pigeon blood red." The clarity is also very important. High quality rubies should be completely see-through with no translucent patches in the stone.
Hardness
- Ruby is the third hardest natural mineral, behind moissanite and diamond. It is rated at 9 on the Mohs hardness scale. This means a real ruby will not smash if hit with a hammer, unlike glass. This hardness is what makes rubies such a good jewelry material, as it is possible to cut the ruby into shapes without damaging the stone. It also has a compressive strength of 2 gigapascals, or the amount of pressure needed to squash the stone.
Light Properties
- Along with color, clarity and hardness, rubies have other properties that make them good for other applications. They have a refractive index of between 1.76 and 1.77 and a double-refraction index of 0.0008. This is why they are commonly used as lenses for lasers in medicine and for holographic cameras.
Other Properties
- Rubies have a melting point of 2040 degrees Celsius and a density, or specific gravity, of 3.91 to 4.10 grams per centimeter cubed.

Rocks & Minerals